What is limestone country?
The limestone country of the Yorkshire Dales National Park is of national and international biodiversity importance.
Limestone pavementat Southerscales
As the name implies the distribution of limestone country habitats is directly linked to the extent of Carboniferous limestone. Consequently the majority of the limestone country of the National Park is concentrated in the uplands around Ingleborough, Malham and Wharfedale.
In these areas the Great Scar Limestone, laid down on seabeds some 300 million years ago dominates the landscape and forms the giant outcrops of Malham Cove and Kilnsey Crag as well as the extensive limestone pavements. The soils lying over this rock are usually very thin and of low fertility and, in combination with consistent grazing, often results in a rich diversity of lime loving grasses and wildflowers for which the limestone country of the Dales is famous.
Outside of this area, limestone habitats are limited in extent associated primarily with outcrops, cliffs and screes associated with the Yoredale Series which overlays the Great Scar Limestone further north.
Small Base-Rich Wetlands
Fed by mineral – enriched calcareous (base rich) water these support a number of important plants which include the nationally scarce bird’s eye primrose.
Limestone Pavement
Limestone pavements consist of horizontal Carboniferous limestone, corrugated and furrowed by chemical weathering, with deeper fissures or ‘grikes’ and separated blocks or ‘clints’.
Calcareous Grassland
The dissolved limestone and low nutrients in soils in the limestone country favour a high diversity of lime-loving grasses and herbs. These include blue moor-grass dominated upland grasslands and the more widespread lowland type dominated by fescues.
Natural Lime-Rich Lakes
Lakes like this are extremely rare and unusual because limestone substrates are free draining. Malham Tarn is rich in calcium, but poor in other nutrients. It is particularly important for its submerged beds of stoneworts (Chara spp).
Rock Outcrops, Cliffs & Scree
The majority of natural cliffs in the Dales occur in limestone areas. They support species such as wild thyme and blue moor grass in association with specialist cliff species such as common whitlowgrass, hairy rock-cress and the rare winter hutchinsia.
Caves
The Yorkshire Dales National Park is renowned for its caves the majority of which are in the limestone areas of the Park. It is the geological and archaeological interest of the caves which is of primary importance as well as their recreational use for potholing. Caves do however, provide habitats for a number of important species.
Limestone Quarries
There are many disused quarries in the Yorkshire Dales National Park the majority of these being situated in limestone areas.
Purple-Moor Grass & Rush Pasture
These are wet meadows or pastures containing a species-rich mixture of grasses (especially purple moor grass Molinia caerula), sedges, herbs and mosses.
